Blockzilla- What to look for?

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cubcadet70

New member
Gonna look at a used blockzilla motor tomorrow. Just curious about the difference between blockzilla 1-3? How to find what it is by looking on the outside? Need to know the specs how big I can sleeve the motor? The current owner don't know any specs. All he knows it used to be a Jr dragster motor. Thanks.
 
the head bolt pattern is different from a 1 2 and 3. the sidecover and breather plate from a 2 will fit a 3. but the head bolt pattern is the main difference. i wouldnt mess around with a 1 or 2. if you can get bz3 the bore will be right at three iinch with plenty of room. Make sure you to put the 7/8 journal 3 inch crank in it as well.
 
Another question. If it's a 1 or 2 blockzilla can they be sleeved for a bigger bore? If so what's the biggest bore I can do? Without putting a head strap on it?
 
cubcadet70 said:
Another question. If it's a 1 or 2 blockzilla can they be sleeved for a bigger bore? If so what's the biggest bore I can do? Without putting a head strap on it?
Click to expand...

No stamp to say what is what
And you can install a little bigger sleeve in each one. But the 1 and 2 can't go 3" bore without serious mods. Bolt hole relocation and welding.
 
The Blocky 3 is by far the favored, if you want to run at more than 14.5 ci.
The Blocky 1 and 2 are nearly the same. Making a very simple head bolt change upgrades the 1 to a 2. Neither of these can approach the 3 for potential out displacement.
The 3 however, almost cannot be run at 14.5 because of the 3+" bore.
The 3 is not manufactured any more...for several years in fact.
Hope this helps.
 
Does anybody have any head bolt spacing specs between the 3 blocks do indentify them? I'm gonna bring my calipers. I have plans to run it more than 14.5ci. But no more than 20ci. I'm sooo green about them blockzilla. I'm hoping to find some tell tell signs on the motor how it's built to see what it is. Maybe I can try to convince the owner to take the head off and measure the bore and sleeve.
 
If you look on the bottom of the block it should say what model it is early ones say nothing or just BZ. I could be corrected but 2 and 3 are same head bolt pattern, with 2 being a small bore vs 3 being big bore. 2's can be resleeved to big bore just like 3. You can make 1's big bore by welding up 2 bolt holes then drilling and tapping 2 new holes then resleeving.

Make sure ports are not hogged out ie exhaust side(jr drags usually hog them out and too big for dirt oval). Ask to pull head and check bore size. JMO
 
Thanks guys for the help. I hope to take some pics tomorrow and just in case I don't figure the block out I will post and have you guys help me out. Gonna try to ask the owner to take the head off. Since it's a simple procedure and copper head gaskets can be reused. So nothing lost there. Just gained more information about the motor.
 
I was concerned about the info: you recieved here.
To provide you with accurate info I got out three Blocky's....a one, two and a three.....to reacquaint myself with the variations.

The Blocky 1 and 2 are distinguished by a different location, of two of the head bolts. The "1" can be made like the "2" by slightly changing the
bolt hole pattern.....which is a simple job.

Secondly, the Blocky 2.....on the bottom side, has Blockzilla 2 inscribed in it, from the factory. The Blocky 1 does not.
The bore of 1 and 2 is the same.

The Blocky 3, has the 3" bore.....and has an entirely different head bolt pattern.
There are 9 head bolts in the Blocky 3. There are 8 head bolt holes in the 1 and 2.
The Blocky 3 also has NO head bolt at the front edge (farthest away from the valves to the very front of the block.)
I'd just look for the head bolt hole in the very front of the head. If it has a bolt hole, it is NOT a Blocky 3. The other 2 can
be used with a little work, interchangeably.
Hope this helps. .....Paul Doss (PD Power)
 
Thanks PD that's what I was looking for. Sadly when I googled it there was no write up articles about the Blockzillas and how to accurately ID them. That's why I asked on this site to find out. If there's 9 head bolts on the blockzilla 3 and 8 on the 1 and 2. Then it should be easy to ID the 3.

Thanks again!
 
The front of the Blocky's is round....as the block goes around the cylinder itself. Right in the middle of that round section.......there will NOT be a bolt, if it's a Blocky 3.
In the Blocky 3 the two front bolts kind of straddle the upper part of the bore. And, as mentioned, ONLY Blocky 3's have 9 headbolts.
Blocky 1's & 2's .... have a bolt right at the front, dead in the middle.
All Blocky 2's are stamped Blockzilla 2 on the bottom. Blocky 1's have no such stamping.
With that knowledge, you now have a positive way to identify the three models of Blockzilla.
Hope this helps whoever reads this stuff. ............Paul D.
 
PD thanks again! All what you said is a very good write up. Needs to be a sticky somewhere on this site how to correctly ID a blockzilla motors. :) I'll be looking at the motor in a couple hours. I'm hoping I will be able to ID the motor.

Thanks again!
 
Looked at the motor. Has Clements finned head, Clements side cover, Clements breather cover, Clements flywheel. Said to have a stroker crank. Has 8 bolt head. No marking on the block. I'm guessing it's a blockzilla 1. But it don't have angle ports. HL368 alky carb on it right now. What do you think it's all worth price wise?
 
But my real question is after some work refreshing the motor. Can it be competitive against 20ci Briggs flathead modified?
 
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